Tenter frames are used by the textile industry in the drying or heat setting of fabrics as the fabric is conveyed through a high temperature dryer. The opposite side edge portions of the fabric are carried through the dryer by a pair of tenter chains with the forward runs of the tenter chains being guided along and rubbing against vertically disposed bearing surfaces of each of the guide rails. Tenter clips or the like are carried by the chain and grip the fabric to stretch it between the spaced-apart tenter chains. The tenter chains carry the fabric through the dryer at a high rate of speed so that substantial frictional forces are generated by the rubbing motion of the tenter chain against the guide rails.
It is the common practice to apply lubricant along the areas of engagement between the tenter chain and the guide rails to reduce wear and to prevent the build-up of excessive heat generated by the frictional forces. Special types of greases, oils, graphite, and other lubricants have been developed to provide the proper amount of lubrication and to prevent staining of the fabric by the lubricant employed. These special types of lubricant are very expensive. Even with the use of these expensive types of lubrication, the friction is still not reduced to the point that the chain and guide rail are not subjected to excessive wear, and the fabric can become stained by the lubricants. If the lubricant contacts the fabric, the stains have a tendency to be set in the fabric by the high temperatures generated in the dryer.
In an attempt to reduce the amount of lubricant required, and to eliminate the problem of staining the fabric with large amounts of lubricant being applied, it has been proposed that various types of slide blocks or plates be carried along by the chain and/or the tenter clip for engagement with the guide rail and to thereby reduce the frictional rubbing engagement therewith. The wear plates heretofore employed have been either of the hard, wear-resistant material type or of a low friction type material. It is also known to provide roller bearings on the chain clip support members and/or the tenter chain in an attempt to reduce frictional wear and to reduce the amount of lubricant which must be applied to the tenter chains. In some instances, both the use of rollers and wear plates or strips have also been suggested. However, in each of these instances, the use of wear strips and/or friction reducing rollers requires considerable modification of the construction of the guide rails and/or the tenter chains and the replacement of the wear plates and/or rollers can be expensive and time consuming.